That's the levelized cost over the lifetime. Hydrogen storage is expensive to both build and maintain.
The issues include hydrogen embrittlement, constant leakage and safety issues. Containers don't last. H2 is the smallest molecule. It gets into the containers and wears them out and leaks away. Casing and seal damage is constant. Pressure vessel storage loses little below 1% leakage per day.Liquid hydrogen storage is about 1-3% leakage per day. Salt cavern storage much less but they have problem of H2S generation
by Micro-organisms.
I don't see how you can compute that cost if you don't know anything about the amount of energy that goes into and out of the container, and how often that happens.
